Please explain the "expense of third order", which of course is more important. I had not heard that, but the improvement in even is small that I have read.
I should get over and re-read Linkwitz on the subject.
As mine will be inside a BP-4 the sticking out is not an issue. Deluge today so not picking up the wood. Glue drying on the new center cab. Stir crazy.
I should get over and re-read Linkwitz on the subject.
As mine will be inside a BP-4 the sticking out is not an issue. Deluge today so not picking up the wood. Glue drying on the new center cab. Stir crazy.
Reducing the 2nd causes an increase in 3rd, and it is generally accepted that it is preferable to have 2nd higher than 3rd, so you are changing a fairly benign distortion for one that is more annoying.
And one gives up aome of the advanatages of push-push.
It is worth trying if you have cheap woofers, but if you have good woofers it is a waste of time (to quote Nick Mckinny),
dave
And one gives up aome of the advanatages of push-push.
It is worth trying if you have cheap woofers, but if you have good woofers it is a waste of time (to quote Nick Mckinny),
dave
I was able to get 12 more db at 31.5 hz and 8 more db at 40 hz at the same distortion level 5% after inverting one of the drivers in my bandpass test.
Start reading at post 108: A tale of 12" subwoofers, distortion and 15 dollars.
Start reading at post 108: A tale of 12" subwoofers, distortion and 15 dollars.
Inverting the driver will not gain you any dB, something is wrong, perhaps wiring the driver out of phase?
Speaker distortion measurements have been shown by Geddes to be not very useful and it is well known trhat single number THD is a completely useless number.
dave
Speaker distortion measurements have been shown by Geddes to be not very useful and it is well known trhat single number THD is a completely useless number.
dave
this is max spl at 5% distortion. I am supplying more power until I reach a 5% distortion threshold.
Actually I just measure until the 2nd or 3rd harmonic hits -25db. It's useful information to me. The drivers that do well in this test sound cleaner to me especially in the deep bass when I listen to a track like Micky Hart's giant bass drum in Temple Caves. A 12" sub can fall apart even at moderate levels of 80db with this song.
I had never seen that. Much thanks. Actually makes the box design easier as better clearance for the front ports.
Seems the discussion of push-pull that I found years ago when the Orion was first being developed is no longer there. Only the discussions of the di-pole H frame.
I see he was still using them, dipole of course , but the technical discussion I think I remember is not to be found.
To help my project ( being lazy that is) I found a 4th order HP 20 Hz filter on e-bay for $10. A couple months wait I am sure, but did not feel like building one and not predisposed to buy a new DSP plate just to get it.
Curious, with in use filters in place, I can make a BP-4 mirror a sealed box within half a dB. But, sealed does not get me the mechanical filtering and I get considerably lower excursion in the bandpass.
To help my project ( being lazy that is) I found a 4th order HP 20 Hz filter on e-bay for $10. A couple months wait I am sure, but did not feel like building one and not predisposed to buy a new DSP plate just to get it.
Curious, with in use filters in place, I can make a BP-4 mirror a sealed box within half a dB. But, sealed does not get me the mechanical filtering and I get considerably lower excursion in the bandpass.
Managed to draw up a package in BP-4 with the drivers back to back so I can clamp the magnets. Pretty convoluted.
Got a model for the RS150-4/Seas DXT to be flat within 1 1/2 dB across the band. If reality is close, I'll be a happy camper. Excursion is still higher than I want, but I do not have the physical space for larger or more mid-bass. It was a bit tricky getting it smooth and keeping the impedance above 6 Ohms. At 2.62V, I measure less than .5% HD 100Hz up. I just hope the sub comes in close.
Got a model for the RS150-4/Seas DXT to be flat within 1 1/2 dB across the band. If reality is close, I'll be a happy camper. Excursion is still higher than I want, but I do not have the physical space for larger or more mid-bass. It was a bit tricky getting it smooth and keeping the impedance above 6 Ohms. At 2.62V, I measure less than .5% HD 100Hz up. I just hope the sub comes in close.